Grinding machine



March 9,1926. 1,575,713

C. G. OLSON enmnn ze momma Filed August 1923 4 Sheets-Sheet 1 March 9 1926.

1,575,713 C. G. OLSON GRINDING MACHINE Filed August 1 1923 4 Sheets-Sheet 2 March 9 1926. 1,575,713

c. G. OLSON GRINDING MACHINE Filed August 1 1923 4 Sheets-Sheet 5 47W W: 0/ x w? March 9 1926.

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GRINDING EACHJINE.

Application filed August 1, 1928;. Serial 655,016.

To all whom it my concern: 7

Be it known that l, CARL G. Orson, a citi-' zen of the United States, residing at Chicago, in the county of Cook and State of llllinois, have invented a certain new and useful Improvement in Grinding Machines, of which the following is .a specification.

I My invention relates to grinding machines, and is especially useiul for grinding 10 articles having relieved teeth such, for example, as hobs. In relieving the teeth of cylindrical cutters, of which hobs are an example, there is a relativemovement of the tool and the worktoward and away from each other while'the cutter is being rotated.

This relative movement is usually accomplished by having the tool unit and the work unit of the machineslidably connected and actuated by a cam whichis geared to rotate intimed relation to the work. An example of such machine is a backing-0d lathe, which has been well known for many years. The relative movement of the work and the tool vin some of the more recent unit or the work unit of the machine swing on pivots. The former construction is shown in my Patent No. 1,259,770 granted March 19th,v 1918, and the latter construction is shown in the patent issued to me and F. W.

England July 5th, 1921, No. 1,383,843.

The grinding of the teeth ofhobs is an 0 rationof such refined precision that the slightest wear in the operating mechanism of the grinding machine may causethe cutting edges of the hob teeth to vary from the true he ix, and when this occurs even to a fraction of one one-thousandth of an inch "the hob will not produce good gears. 'The'machines in w ich the tool holder or the work holder oscil ated about a pivot to produce the relief,- were an. improvement over had the disadvantage that themovement wasnot strictly rectilinear (radial) andthe object of mypresentinvention is to produce a machine in which the movement will, within the ordinarytially in a'straight line,

in hand. H Another'object ofthe invention 1s to pro- Y duce a machine of simplified construction,

grinding .ma- 25 chines is efiected by having either the tool the machines of the sliding type but.

. tween the rolling work holder imits of operation, be substan-Y and radial with respect to the hob cutter or other piece of work especially with respect to the parts which cause tlns radial movement, and also to produce a machine in which the wear and the effects of wear will be reducedto. a minimum. Generally speaking, one of the two elements (the work holder or the tool holder) is mounted in an element which is adapted to roll back and forthupon a track to effect ing the relief in the teeth of the work. According to the illustrated form it is the work holder which rolls back and forth toward.

and from the ,grinding tool. In the illustrated case, in which the work is a hob, means are provided for feeding the work spindle axially in. accordance with the helix or lead of the hob teeth.

I obtain my objects by the mechanism the radial movementnecessary for producillustrated in the accompanying drawings,

in which-- Figure 1 is an elevation of the machine,

chiefly in'axial section.

Figure 2 is a sectional 2-2 Fig; 1. r

Figure 3 .is a sectional elevation on the line 33 Fig. 1.

elevation on the line towards the right in Figure 1. In this view certain parts are broken away to better reveal the internal construction.

Figure 5. is a perspective view showing the chief operating parts, more intimately connected with my present invention.

Figure 6 is manner of holding the rolling element upon the track. The view is an end elevation.

Figure 7 is a side elevation partly in section of the parts shown in Figure 6.

Figure 4 is an endelevation looking especially those a detail showing a modified Figures 8 and 9 are similar to Figure 6 I but show still other modifications of the mechanism for holding the rolling element upon the track.

Figure 10 is a fragmentary perspective view of a modified form of connectlonba and the tracks on whichit rolls. f

Like numerals refer to like parts throughout the several views. 1

In the illustrated a... of the invention the work consists ofa hob 1,'which is rigidly secured to a work spindle 2.- This spindle mounted in a tool post rising rom a carriage -11. This carriage is capable of the usual adjustmentsand as it is not intimately concerned with the novelty of my present invention, need not be described-in detail. A tool carriage suitable for the purpose 1s described in detail in the copending application of Charles J. Irwin, for hob grinder, filed May 3, 1923, Serial No. 636,32

The work spindle 2 has a threaded portion which has a helix angle corresponding to the helix angle of the "hob teeth. It

works in a nut 21 secured by a set screw 22 or other appropriate means in a rollmgelement 24 which will be hereinafter described.

The spindle has a supplemental bearing in a sleeve 26 which is secured in said rolling element by means of a set screw 28 or other suitable mechanism.

The work spindle is driven by means of a gear 30 which is rigidly fastened to it andmeshes with a wide-faced pinion 32. The means for supporting and driving this pin-- ion ma be considerably varied and need not be escribed further thanto say that the y a trainof gears 40, .41, 42, 43. Gear43 is fastened to a power shaft 46 which has a stationagy axis,iand is driven in any suitable manner, for example, a sprocket wheel 48 and chain 50. In practice the latter is usual ly driven by an electric motor (not shown).

* With the exception of the'rolling' element 24 the parts thus far described arenot herein claimed as new. Referring now tosaid rolling element and the parts which relate moreintimately to the essence of the inventionz In the form' illustrated the rolling ele-' ment, which is represented in general by the numeral 24 and may be regarded as the rolling work holder, is in the general form of a housing which enclosesthe gear 30. Y It has acylindrical cover 25. It has ri 'dly connected 'to it two cylindrical trearfix Tfl which are supported'by tracks secured to the framework 64 of the machine. These tracks are -parallel to each other and intend crosswise to the axis of the-work. n the form shownin Figures 1 to 4 of the drawing the rolling work holder does not restjdirectly upon t is tracksbut upon steel tagizs or hands 64. One end of thesetapes is toned by screws 66 to the surfaceof the connected by an arm 88 having inio'n has a stationary axis and is'driven x E of Figure 10 According to the preferred -toothed clutch 100.

in the reverse direction to shift track and the other end by screws 68 to the tread 59. These bands are of considerable width and are rigidly fastened to the respective parts. The result is that they effectually prevent movement of the rolling element in an axial direction. They also prevent slippage, angularly, of the treads relatively to the tracks. As a special precaution againstaxial and angular .slippa c the expedient shown in Figure 10 may he employed, in which case there is an additional band 72 connecting the parts but arranged op sitely. The treads are of considerable ameter of the hob, and it will be evident that when the work holder rolls backand ameter compared with the dihob teeth the movement of the ho toward and from the grinder will, to all intents and u'po'ses, be in a straight line'radial to the o Now considering the mechanism for causing the work holder to rollback and forth upon the tracks:

A steel band or tape 80 is fastened atone end by a screw 82 to one ,of'thetreads of the rolling element and at the other end is a link 84 and pivot pin 86 to a block which is adjustable lengthwise on a stationary pivot 90, as best shown in Figures 2 and 5. The free end of this armhas a nose 92 which engages the actin surface of a cam 94 fastened to a cam sha t suitable hearings in the framework 62 of the machine as shown in the lower portion design this shaft is in line with the power shaft 46 previously mentioned and is connected thereto through. the agency of a This clutch makes oneway engagement SQ that when the power shaft is rotating in the forward direction "it will rotate the cam but when it is rotating the work spindle 2 back to initial position, axially, the cam will not be rotated.

The band or strap 80 operates chiefly in tension and-in a direction to move the work toward the grinder. Thevreturn movement -or backing off is accomplished by means of "a tension spring 102 shown in Figures 2 and 5. This spring is connected at one end to the tread'59 by a strap104 and at the other end is connected by a threaded ad- ,.]'usting of the-framework 62. Thus the strap 80 pulls the work holder forward and the rod '106 and nut 108 to a portion spring 102bpulls it back. when the tension of strap 8 is released:' The spring also has the effect of keeping the nose of the 96. This shaft is journaled in arm 88in close contact with the cam, and

of keeping the workhold'er down on the track. This latter, effect is produced at the opposite end of the workholder bya tenframework by pins 105 secured 'to the respective parts.

The manner of mounting the rolling workholder upon the track and preventing slippage may be'varied. For example, in Figures 6 and 7, I have shown a connecting link 110, one end of which is pivotally connected by a pin 112 to the-trackfiO". The

other end of the link is pivotally connected B5 to the workholder by a pivot .pin 114.

A similar result may be accomplished in the manner shown in Figure 8,- in which the slippage is prevented bya stationa rack 120, which is engaged bya gear 122 ibrmed on the rolling workholder. v

Still another form is illustrated in Figure 9, in which casea pin 130 is secured to the rolling workholder and's lid es in a vertical slot 132 formed in aplate 134 secured at the side of track 60;

The operation of -the machine will befevi- I dent from the foregoing.- Assuming the machine to be set in proper position for starting, when the power mechanism rotates the wide-faced pinion 32, the latter will rotate the gear 30 and through it the work spindle 2. This will produce two effects,

viz., the rotation of the hob about its own axis and the axial travel of the hob due to the action of the lead screw 20 and lead nut 21. The power shaft 46 will rotate cam shaft 96 and cam 94, thus causing .a verti-- cal movement'of the band or strap and this in turn will cause the workholder to roll back and forth'upon the track 60, thus movingsthe hob in substantially a straight radial line toward and from the grindei hto e amount of the relief may be regulated by s'litably adjusting the block along arm 8 it will be evident that this construction not only makes it possibleto produce a sub-- stantially rectilinear movement of'the hob toward and from the grinder, but does it as the result of a rolling'action of the work holder in distinction to a sliding action. It

is well known that a rollingact on produces less friction thana sliding action, and the result is that in my machine friction will be reduced to a minimum. This not only/ e.-

duces the amount of power and lubrication required but, more important still,minimizes the weanwhich will occur upon the parts which determine the'accuracy of the work. As previously explained this latter 0 aracteristic is of great importance in view of the small degree of tolerance ermissible in the grinding of hobs. Anot er advantage of my machine is that the parts may be made large, that is, the tracks and treads may be of comparatively large dimensions, thus still further making for accuracy of operation and reduction of wear.

One of-the characteristics'of design by which I am enabled to obtain the three-fold 10 Letters Patent is:

1; A- grinder havinga framework provided with a track, a tool holder and a worki holder, one of which is. adapted to roll upon the track and the other "is the 'tool and the work into contact at a point approximately as far from the plane of' the track'as the radius of, the part which rolls upon the track.

2. A grinder having a framework ed with a track, a tool holder, a wor holder having a rolleradapted to roll upon the track, the tool holder. being adapted to pre-' sent the tool to the work at a point approxi- .mately as the radius of the workholder, and means for rolling the workholder back and forth. along the track to thereby move the work bodily and approximately radially toward and from the tool. y

3'. A grinder havin a framework provided with a track, a cy indrical work carrier for rolling on said track, a workspindle, concentric with the work carrier and rotatable therein, means rotating the spindle, and a tool holder adapted to present -thetool to the work ,at a oint approximately as far from the (plane 0 the track as the radius of the cylin rical work carrier. v4;. A hob grinder having a grinding element, a work supporting roller, a main frame having a plane surface-for'supporting said roller, means for preventing slipping. between said roller and its said su porting surface," means for rolling the rol er bac and forth toward and from the grinder, a

centrically therewith, and means for rotat: ing the work spindle about its-axis.

5. A hob'grinder having a grinding elethe wide faced pinion 32. 7e

1. claim as new and desire to secure by 8 adapted to bring 8 rovidas far from the plane of the track,

for-rolling the roller along the track, means for independently work spindle journaledin the roller, conment, a worlr supporting roller, a main.

frame having a planesurface for support: ing said roller, means for preventing slipping between said roller and its said sup- 1 porting surface, means for rolling the roller back and forth toward and from the grinder,

a work spindle journaled in'the roller, concentrically therewith, means for rotating the trend of the roller for the work toward and from the work spindle about its axis, anda lead screw for simultaneously shifting the work spindle longit'udinally. i

6. A hob grinding machine having a main frame, a grinder mounted thereon, a traclron the mam frame, a work holder having-a roller adapted to roll on said track to move the work toward and from the grinder means for causing'the work holderback and forth upon the track, and

connector fastened to the work I means for alternately pulling centrically,

and releasing the connector to thereby cause the roller to roll forward on the track, and resilient means for returning. the roller when the connector releases it.

8. A hob frame, a grinder mounted thereon, a work spindle, means for rotating the work.- spindle about its axis, means for simultaneously shifting the work spindle along its axisin accordance with the-lead of the hob, a frame in which the work spindle is journaled, rollers on said frame-concentric with v the axis of the work spindle, tracks on the grinding machine having a 'main scribed my name.

main frame for supporting the rollers, positive acting means for rolling the rollers forward intermittently toward the grinder, and

resilient means'for rollin the roller backvtracks on the main frame for supporting the rollers, a gear wheel for rotating the work spindle and a pinion for rotating said gear, the pitch circle of the pinion being tangent to the projected plane of the tracks.

10. A. hob grinding machine having a main frame provided with a grinder, a workspindle, a lead screw on the work spindle, a gear wheel fastened to the work spindle for rotating and shifting it, a wide faced pinion meshing with said gear, a rolling frame in which the work spindle is journaled, said rolling frame having rollers concentric with the spindle tracks for supporting'said rolling frame, the plane of the tracks, if extended, being tangent to the pitch circle of the pinion, and means for rolling said rolling frame back and forth on tracks to the work.. a

In Witness whereof, I have hereunto subproduce relief in the teeth of CARL G. oLso i, 

